Biology and postnatal development of organ systems of cynomolgus monkeys (Macaca fascicularis)

Abstract

Mammalian development is tightly programmed and highly regulated. Morphological and functional development simultaneously occurs in various organ systems from gestation to early postnatal life. Although animal maturity is often defined as sexual maturity, the maturity timeline of other organ systems varies. 1,2 Fetal and early postnatal life is a critical period of organ system development; adverse effects during this stage can cause life-long impacts.The developmental differences between humans and animal organ systems have been investigated during their lifespan. 1,2 For example, organ system development in the cynomolgus macaque (CM) during the first 3-6 months of postnatal life corresponds to the first 1-2 years of age in humans. 1 It is essential to understand the comparative biology and developmental windows of organ systems and age correlation among different species for biomedical research and nonclinical safety assessments.Nonhuman primates (NHPs) are the closest phylogenetic species to humans, especially apes and macaques. 3,4 The rhesus macaque (Macaca mulatta) was the most used NHP species in biomedical research in the last century. Biomedical information for rhesus macaques is frequently extrapolated to CMs. 1,5,6 The CM is the most